How COVID vaccines might be causing blood clots with low platelets

Rare cases of severe blood clotting combined with low platelet count, dubbed thrombotic thrombocytopenia, reported for two adenoviral vector COVID vaccines have raised questions about whether the adverse event is related to the vaccine modality and, if so, what the impact will be on ongoing and future adenoviral vector vaccine development.

Right now, there are more questions than answers. BioCentury’s analysis of the leading hypotheses finds no obvious pattern in the design of six authorized vaccines that could inform future vaccine optimization...